White muscle disease (WMD) is a selenium responsive myopathy. Since calcium accumulates in heart and muscle of WMD lambs, the ability of fragmented sarcoplasmic reticulum (FSR) from normal and WMD lamb muscle was investigated. As the severity of WMD increased, a correlated decrease was found in the ability of the FSR to sequester calcium. In order to obtain information on the reason for this loss of ability, FSRs will be purified from muscle of normal and WMD lambs. The chemical properties of these two preparations will be examined. Among the planned analyses are subjection to sodium dodecyl sulfate polyacrylamide gel electrophoresis, fatty acid analysis, amino acid analysis, and phosphorus determination. The ATPase activities of these preparations will also be determined. A low molecular weight (10,000) selenium containing protein will be purified from hearts of lambs and characterized with respect to its selenium content, amino acid composition, more detailed molecular weight, and any absorption properties. Likewise, glutathione peroxidase, a selenium requiring enzyme, is planned to be purified also from cardiac tissues, and characterized with respect to selenium content, amino acid composition, molecular weight, and any absorption properties. The amount of glutathione peroxidase and the low molecular weight selenium containing protein are dependent upon the selenium status of the animal. BIBLIOGRAPHIC REFERENCES: Chen, R.W., P.D. Whanger and P.H. Weswig. Selenium induced redistribution of cadmium binding to tissue proteins: A possible mechanism of protection against cadmium toxicity. Bioinorganic Chem. 4:125 (1975). Whanger, P.D. Weswig, J.E. Oldfield, P.R. Cheeke and J.A. Schmitz. Selenium and white muscle disease in lambs: Effects of vitamin E and ethoxyquin. Nutr. Reports Intern. 13:159 (1976).